Fuel system for engines



April 2, 1940. vM Q PRICE 2,195,825

FUEL SYSTEM FOR ENGINES Filed May 11, 19.57 4 Sheets-Sheet 1 A TTORNEYS.

APl'l 2 l940- N. c. PRICE 2,195,825

FUEL SYSTEM FOR ENGINES Filed nay 11, 1937 4 sheets-sheet z 'INVENTORTZal/'Fryk C. /ALQ April 2, l940 N. c. PRICE 2,195,825

FUEL SYSTEM FOR ENGINES Filed lay 11, 1937 4 Sheets-Sheet 3 E ig.5.

INVENTORY y BY 73M( ATTORNEYS.

April 2; 1940. I' N. c. PRlclzE Y 2,195,825'

I FUEL SYSTEH FOR ENGINES ined lay 11. 1957 sheets-sheet 4 Fig.'

Fue L Ti/ming IN VEN TOR.,

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ATTORNEYS.

Patented Apr. 2, 1940 PATENT OFFICE FUEL SYSTEM FOR ENGINES Nathan' C.Price, Berkeley, Calif., assigner to Universal Engine and Propeller Co.,Alameda, Calif., a corporation of California Application May 11, 1937,Serial No. 142,001 v 9 Claims.

The present invention relates to a fuel induction system especiallyadapted for aircraft engmes.

The principal object of the invention is to provide a fuel inductionsystem of the positive pressure or super-charger type in which theliquid fuel is properly proportioned to the air at all times and underall conditions of speed, load, and atmospheric pressure. A second objectis to provide a system in which the air and liquid fuel are keptseparate until just before entering the engine cylinder,`and in whichthe liquid fuel distribution lines leading to the various cylinders arehoused within the air induction system,I

thereby improving vaporization of the fuel by subjecting it to theincreased temperature of the air delivered by the super-charger blower,and eliminating any danger from re in the event of leakage from a fuelline. Another object is to provide a system in which the high tensionignition distributor and the conductors leading to the spark plugs ofthe cylinders are housed within the air induction system, therebysubjecting them to super-atmospheric pressure and pre'- venting coronadischarge losses from said distributor and conductors under theconditions of reduced atmospheric pressure encountered at highaltitudes.

These and other objects and advantages of the invention will becomeapparent from the following specication, which should be read with theunderstanding that changes, within the scope of the claims heretoappended, may be made in the form, construction, and arrangement of theseveral parts herein shown and described, without departing from thespirit of the invention as defined in said claims.

A preferred form of the invention is herein described and illustrated asembodied in an aircraft engine of theradial cylinder type. It willl beapparent, however,'that the invention can be applied to engines of othertypes without material change. Only such parts of the engine as arepertinent to the invention are shown and described herein.

In the drawings,

Fig. 1 is a partial rear end' elevation of an engine provided with myfuel induction system.

Fig. 2 is a part sectional front end elevation,v

enlarged, of the induction manifold.

Fig. 3 is a longitudinal section of the rear end portion of the enginetaken on the line 3-3 of Fig. 1, and enlarged, showing the air blowerand fuel distributor.

(Cl. 12S-119) Fig. 4 is a plan view, enlarged, of the fuel compensator.

Fig. 5 is a vertical section of the same, taken on the line 5-5 of Fig.4.

Fig. 6 is a partial vertical section of the same, 5 taken on the line 66 of Fig. 4.

Fig. 7 is a part sectional side elevation of the rear end portion of theengine, showing the position of the fuel compensator with respect to theair intake and blower, the sectional portions 10 being taken in avertical plane indicated by the line 'l-T of Fig. 1.

Fig. 8 is a diagram showing the functional arrangement of the severalparts.

Throughout the following specification, the l5 word fuel will be used asmeaning liquid fuel capable of being vaporized or atomized and burned inthe engine cylinder when mixed in proper proportions with air andsuitably compressed. The fuel may be gasolineof high Volatility, forwhich the particular engine herein illustrated has been designed, or itmay be some other fuel of lower volatility. The invention contemplatesal blower or other means for supplying air to the cylinders undersuper-atmospheric pressure, means for supplying fuel under constantpressure, a fuel compensator for regulating the amount of fuel suppliedin proper proportion to the amount of air under all conditions ofoperation, and a conduit system for separatelyY conducting the air andthe fuel to the intake ports of the cylinders, said fuel being sprayedinto the air stream at points close to said intake ports.

Referring more particularly to the drawings, the reference numeral Ildesignates the main shaft of the engine, I2 is the crankcase, and I3,

Figs. 1 and 2, are the rear cylinders of two adjacent banks or rows. Thenumber of cylinders in each bank is immaterial, as is the number ofbanks. All the cylinders of each two adjacent banks are served by acommon intervening manifold I4 having suitably spaced branches I5connected with the cylinder inlet ports I6. The 'exhaust manifolds andthe inlet and exhaust valves of the cylinders are immaterial to thepresent invention, and are therefore illustrated conventionally in thediagram, Fig. 8, in which only one cylinder is shown for the sake ofsimplicity.

At the rear end of the engine the manifold I 4 50 turns inwardly, i. e.toward the shaft I I, and connects with a branch II leading outwardlyfrom the discharge duct I8 of a blower I9, Fig. 3, which surrounds andis driven by the shaft II, and has an inlet chamber 20. The blower drawsair in through an inlet pipe 2|, Fig. 7, having a butterfly valve 22which is the throttle valve of the engine. It will be seen that theparts hereinbefore described constitutes an air induction system, theair being drawn in through the throttle controlled intake 2| by theblower I9, and forced out to the various cylinders, at superatmosphericpressure, through the manifold I4. There may be as many manifolds as isnecessary to supply all the cylinders, each such manifold beingconnected as described with the common discharge duct I 8 of the blower.

Fuel is supplied at constant pressure from any suitable source, notshown, and its flow is regulated in a compensator 23 mounted at the rearof the engine as indicated in Figs. 1 and 7. This compensator, which isshown in detail in Figs. 4, 5 and 6, has a fuel regulating valve whichis controlled both by the ow or velocity pressure of the air in theintake 2| and by the flow or velocity pressure of fuel itself. The fuelenters the unit through a pipe 24, and passes through a venturi throat25, thence through the regulating valve and out through a pipe 26. Theregulating valve is a plug 21, slidable in a cylinder 28. The upper endof said plug moves toward and away from a seat 29, thereby varying theffow of fluid through the outlet 26. The valve plug 21 has a smallcentral port 30, which is closed at its lower end by a needle formedupon the upper end of a stem 3|. A piston 32 on said stem operates in acylinder 33. The lower end of said cylinder, below the piston 32, isopen to the pressure of the fuel in the supply line, through a passage34. The upper end of the cylinder 33, above said piston 32, communicateswith the throat of the venturi through passages 35. The piston 32 istherefore affected by a pressure differential which is a function of thefuel flow, an increased flow increasing the pressure differential andtending to raise the piston, and a decreased flow tending to lower saidpiston. The arrangement of the ported valve plug 21 is such that ittends to keep itself seated lightly on the stem 3|, and thereforefollows the movements of said stem. A needle valve 36, adjustable fromthe exterior, is provided to regulate the effective area of the venturithroat.

'I'he stem 3| extends downwardly through a guide bushing 31, and carriesa second and larger piston 38, operating in a cylinder 39. The lower endof said cylinder 39, below the piston 38, is connected by a passage 40and pipe 4|, Fig. 7, with the air intake 2|. The upper end of saidcylinder, above the piston 38, is open to the atmosphere through apassage 42 and a screen 43, Fig. 6. The lower side of said piston 38 isthereforeexposed to the sub-atmospheric pressure in the air intake 2|,and its upper side is exposed to atmospheric pressure. Hence the piston38 is acted on by the pressure differential existing between the airintake and the atmosphere, which is a function of the flow of air to theengine. A spring 44 tends to resist the effect of said air pressuredifferential.

It will be seen that the air piston 38 and the fuel piston 32 work inopposition. As the throttle 22 is opened and more air flows through theintake 2|, its pressure falls and theair piston 38 and the stem 3| movedown, thereby opening the fuel valve 21 and allowing-more fuel to flow.Such increased now of fuel, however, increases the pressure differentialaffecting the fuel piston 32, which resists the downward movement of thestem 3|. By properly proportioning the various parts, the device can bemade to regulate the fuel in proper ratio to the air supply under allconditions of the latter.

The fuel compensator provides a further automatic regulating function,to compensate for variations in atmospheric pressure due to changes inaltitude. This function is accomplished by an aneroid element 45, Fig.6, mounted in a chamber 46 and exposed to the atmosphere through anaperture 41. The upper end of said aneroid element is fixed at 48, andits lower end carries a needle valve 49 which obstructs, to a greater orless extent, the air inlet 42 leading to the air cylinder 39. Thepassage below the valve 49, shown at 50 in Fig. 6, is for constructionpurposes only, and has no operating function. 'Ihere is a constant ow ofair through the passage 42, due to the pressure differential on thepiston 3B and the leakage around it. As the atmospheric pressuredecreases, due to altitude, the element 45 expands, causing its valve 49to move down and further obstruct the passage 42. This reduces the flowof air through the cylinder 39, thereby reducing the effect of thesub-atmospheric pressure in the air intake 2 I, and reducing the fuel toairl ratio. Thus the proper proportions of fuel and air areautomatically maintained under all conditions of throttle opening andatmospheric pressure.

From the compensator 23, the fuel passes through the pipe 26 to one ormore timing and distributing Valves 26a. (Fig. 8), the number thereofdepending upon the number and arrangement of the engine cylinders. Thedrawings herein illustrate one such timing and distributing valve,designed to distribute fuel to all cylinders of the two banks served bythe air induction manifold I4.

At the rear of the engine, the crankcase is provided with a suitableextension 5I, Figs. 1 and 3, in which the fuel distributor is housedimmediately behind the blower and approximately in line with the end ofthe manifold I4. The distributor comprises a fixed member bolted to thehousing and having an annular upper head 52, Fig. 3, and a central shank53 extending downwardly therefrom. Within the head 52 is a hardened andground annular sleeve 54, and within said sleeve is a rotor 55 fixedupon a vertical shaft 56. A plate 51 is bolted to and. closes the top ofthe headl 52, said plate having an upward extension in which is mounteda ball bearing 58 for the shaft 56. 'Ihe lower end of said shaft carriesa bevel gear 59, and a second ball bearing 60 is mounted between anupstanding iiange on said gear and the stationary shank 53. The twobearings 58 and 60 centralize the rotor 55 accurately within thestationary sleeve 54.

Packing 5| is provided around the shaft 58, preferably at three points,viz): the upper and lower ends of the shank 53, and in the shank of thecover plate 51. Each packing is compressed by a spring 62 held in placeby a suitable retainer 63.

'Ihe head 52 and its sleeve 54 are provided with a radially disposedinlet opening 64 with which the fuel inlet pipe 26 communicates, andwith a plurality of properly spaced radial discharge openings, one ofwhich is shown at 65, said discharge openings being positioned in ahorizontal plane above the inlet opening B4. The inlet opening admitsthe fuel to a space below the rotor 55, and the peripheral ange of saidrotor is provided with a port 66 which registers successively with theseveral discharge ports 85 to permit discharge of said fuel. The rotoris driven lby suitable gearing 61 connecting the gear I8 with the engineshaft II.

Each discharge port 65 of the distributor head 52. communicates, througha suitable connection 68, with a fuel line 69 leading to one of theengine cylinders. All such fuel lines 69 are led through an open passage10 which connects the interior of the distributor housing 5I with theblower discharge branch I1 and the air induction manifold I4, and thenceare carried inside said manifold, as indicated in Figs. ll and 2, to therespective, cylinders connected therewith. In Fig. 3,

only four fuel lines 69 are shown, to avoid confusion, but it is to beunderstood that there will beas many such fuel lines as there arecylinders supplied by that particular distributor. In Figs. 1 and 2,eight fuel lines are shown within the air manifold I6. They may bemounted in 4the manifold in any suitable manner. i

At each branch I5 of the manifold I4, one fuel line 69 is led off intosaid branch, and terminates in a socket 1I formed in the wall of saidbranch adjacent the cylinder inlet port I 6. An injection nozzle 12, of4any suitable type, is mounted in the socket 1I, and serves to spray thefuel into the air stream as said air passes into the cylinder inletport.

It will be seen from .the foregoing and by reference to Fig. 8 that thefuel distributor and the fuel distribution lines leading to the variouscylinders are 'housed within the air induction system. 'I'he interior ofthe distributor housing 5I is open to the air manifold through thepassage 10. Any

v fuel which may leak from a broken or defective fuel line will be drawninto the engine through the air manifold.' Any fuel that may leak from.the distributorvcan be drained off from the bottom of the housing .5Iin any suitable manner, as for example by a small aperture 13, Fig. 3,leading into the air intake chamber 28, from which it will be drawn intothe engine. The only exposed lfuel pipes are the inlet pipe 24 leadingfrom the pump or other source of supply of the compensator 23, and theshort pipe 26 leading from said compensator to the distributor. Thedanger from fire in the event of a broken or leaky fuel line istherefore reduced to a. minimum. Moreover,

housing the fuel distribution lines within the air manifold subjects thefuel to the temperature of the air within said manifold, which isvalways above atmospheric temperature because of its super-atmosphericpressure, and thereby improvesvaporlzation of said fuel. In order toinsure equal distribution of fuel to all cylinders,

the shorter fuel distribution llines' are made I slightly smaller in,diameter than the longer lines.

been omitted from the drawings.

By properly proportioning the diameter of said lines to their length,the friction in all can be made equal.

An ignition distributor 14, Fig. 3, is mounted in the upper portion ofthe housing 5I above the fuel distributor, and is driven by the shaft56.

channel 11 formed in the crank case at the rear being shown in Fig. 3,the shield conduit 19 is connected with the cover plate 18 by a bushing80 which is pressure tight, as well as providing an electrical groundfor said shield.

As a result of this construction, the ignition distributor 14 and thehigh-tension conductors 15 are subjected to the super-atmosphericpressure of the air induction system. Suitable apertures 8I are providedbetween the base of the ignition distributor 14 and the housing flange82 on which it rests, so that the pressure within the fuel distributorhousing passes into the ignition .distributor housing, and thencethrough the passage 16 into the channel 11. The ignition distributorhousing is provided with a tight cover 2' 83. The pressure tightbushings 88 permit the super-atmospheric pressure to the channel 11 topass into the flexible shield conduits 19 of the conductors 15, so thatsaid conductors are maintained under super-atmospheric pressurethroughout their length. Corona losses, which would otherwise occurthrough the'insulation and from the various conducting elements of theignition distributorat the reduced air pressure encountered at high"altitudes, are thereby prevented. In as much as the fuel is not mixedwith the air until just before it enters the cylinder, there is nodanger of ignition of said fuel by accidental electrical discharge fromthose portions of the electrical system that are housed within the airinduction system.

I claim:

1. In an internal combustion engine having a cylinder, means forsupplying air to said cylinder under super-atmospheric pressure, meansfor supplying fuel to said cylinder, an-electric ignition systemincluding a distributor for the ignition current, and an air tighthousing inclosing said distributor, the interior of said housing beingexposed to the pressure of said air supply.

2. In an internal combustion engine having a cylinder, an air inductionsystem therefor operating at super-atmospheric pressure, means forsupplying fuel to said cylinder, and an electric ignition system havinga portion thereof housed within said air induction system.

3. In an internal combustion engine having a cylinder, an air inductionsystem therefor operating at super-atmospheric pressure, a fuel sup-lply system, and an electric ignition system, portions of said fuel andignition systems being inclosed within said air induction system andexposed to the super-atmospheric pressure thereof.

4. In an internal combustion engine having a cylinder, an air inductionsystem therefor. operating at super-atmospheric pressure, a fuel supplysystem including a timing and distributing valve, an electric ignitionsystem including a distributor for the ignition current, a housingenclosing said fuel distributing valve and said ignition distributor,and means for conducting the super-atmospheric pressure of saidairinduction system to the interior of said housing.

5, In an internal combustion engine having a plurality of cylinders,means for supplying air under super-atmospheric pressure, a manifold forconducting said air to said cylinders, means for supplying fuel, meansfor automatically maintaining a predetermined fuel to air ratio, a fueldistributing valve, and conduits for conducting the fuel from saiddistributing valve to the respective cylinders. said conduits beingpositioned wholly withinl said manifold and discharging said fuel intothe supplied air adjacent the cylinder intakes.

6. In an internal combustion engine having a. cylinder, an air inductionconduit for supplying air to the intake of said cylinder, means in saidconduit driven by the engine for raising the pressure of the air flowingtherethrough above atmospheric pressure, means for supplying fuel, amov` able valve operated by the engine for timing the supply of fuel tothe cylinder, an air-tight housing inclosing said fuel timing valve, abranch conduit connecting said air induction conduit with said housing,and a fuel distribution pipe leading from said timing valve through saidbranch conduit and said air induction conduit, said pipe terminating ata fuel discharge orifice positioned within said air induction conduitadjacent to the cylinder intake.

7. In an internal combustion engine having a cylinder, an air inductionconduit for supplying air to the intake of said cylinder, means in saidconduit driven by the engine for raising the pressure of the air flowingtherethrough above atmospheric pressure, means for supplying fuel, amovable valve operated by the engine for timing the supply of fuel tothe cylinder, an air-tight housing inclosing said fuel timing valve, abranch conduit connecting said air induction conduit with said housing,a fuel distribution pipe leading from said timing valve through saidbranch conduit and said air induction conduit, said pipe terminating ata fuel discharge orifice positioned within said air induction conduitadjacent to the cylinder intake, and a drain conduit connecting saidhousing with said air induction conduit.

8. In an internal combustion engine having a cylinder, an air inductionconduit for supplying air to the intake of said cylinder, means in saidconduit driven by the engine for raising the pressure of the air flowingtherethrough above atmospheric pressure, means for supplying fuel, ashaft rotated by the engine, a fuel timing valve and an electricignition timer positioned in adjacent relation and driven by said shaft,an airtight housing inclosing said fuel timing valve and said ignitiontimer, a branch conduit connecting said air induction conduit with saidhousing to raise the pressure therein, a fuel distribution pipe leadingfromsaid timing valve through said branch conduit and said air inductionconduit to a discharge orifice adjacent the cylinder intake, an electricconductor leading from said ignition timer to the cylinder, and anair-tight conduit surrounding said conductor, the last mentioned conduitopening into said housing and receiving pressure therefrom.

9. In an internal combustion engine having a cylinder, an air inductionsystem having a pressure tight conduit for supplmng air undersuperatmospheric pressure to the intake of said cylinder, means forsupplying fuel under super-atmospheric pressure, fuel metering means formaintaining a predetermined fuel to air ratio, said metering means beingoutside said air induction system and being controlled by the pressuredifferentials between the air in said induction system, the fuel, andthe atmosphere, a movable valve operated by the engine-for receiving thefuel from said metering means and timing the supply thereof to thecylinder, said valve being Apositioned Within a portion of said airinduction conduit, and a fuel pipe leading from said valve, through saidconduit, said pipe terminating at a discharge orice within said conduitadjacent to the cylinder intake.

NATHAN C. PRICE.

